/*
 * $Id: stdlib_md5.c,v 1.4 2005-12-05 15:11:29 bacon Exp $
 */

#include <xp/bas/stdlib.h>
#include <xp/bas/memory.h>

/* 
   Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
   rights reserved.

   License to copy and use this software is granted provided that it
   is identified as the "RSA Data Security, Inc. MD5 Message-Digest
   Algorithm" in all material mentioning or referencing this software
   or this function.
 
   License is also granted to make and use derivative works provided
   that such works are identified as "derived from the RSA Data
   Security, Inc. MD5 Message-Digest Algorithm" in all material
   mentioning or referencing the derived work.
 
   RSA Data Security, Inc. makes no representations concerning either
   the merchantability of this software or the suitability of this
   software for any particular purpose. It is provided "as is"
   without express or implied warranty of any kind.

   These notices must be retained in any copies of any part of this
   documentation and/or software.
 */

#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))

/* ROTATE_LEFT rotates x left n bits. */
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

#define FF(a, b, c, d, x, s, ac) { \
	(a) += F ((b), (c), (d)) + (x) + (xp_uint32_t)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
}
#define GG(a, b, c, d, x, s, ac) { \
	(a) += G ((b), (c), (d)) + (x) + (xp_uint32_t)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
}
#define HH(a, b, c, d, x, s, ac) { \
	(a) += H ((b), (c), (d)) + (x) + (xp_uint32_t)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
}
#define II(a, b, c, d, x, s, ac) { \
	(a) += I ((b), (c), (d)) + (x) + (xp_uint32_t)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
}

static xp_byte_t padding[64] = {
	0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};

static void __init (xp_md5_t* md5);
static void __transform (xp_uint32_t state[4], xp_byte_t block[64]);
static void __encode (xp_byte_t* output, xp_uint32_t* input, xp_size_t len);
static void __decode (xp_uint32_t* output, xp_byte_t* input, xp_size_t len);

xp_md5_t* xp_md5_open (xp_md5_t* md5)
{
	if (md5 == XP_NULL) {
		md5 = (xp_md5_t*) xp_malloc (xp_sizeof(xp_md5_t));
		if (md5 == XP_NULL) return XP_NULL;
		md5->__dynamic = xp_true;
	}
	else md5->__dynamic = xp_false;

	__init (md5);
	return md5;
}

void xp_md5_close (xp_md5_t* md5)
{
	if (md5->__dynamic) xp_free (md5);
}

void xp_md5_update (xp_md5_t* md5, const void* data, xp_uint32_t len)
{
	xp_byte_t* input = (xp_byte_t*)data;
	xp_uint32_t index, part_len, i;

	/* compute number of bytes mod 64 */
	index = (xp_uint32_t)((md5->count[0] >> 3) & 0x3F);

	/* update number of bits */
	md5->count[0] += ((xp_uint32_t)len << 3);
	if (md5->count[0] < ((xp_uint32_t)len << 3)) md5->count[1]++;
	md5->count[1] += (xp_uint32_t)len >> 29;

	part_len = 64 - index;	

	/* transform as many times as possible */
	if (len >= part_len) {
		xp_memcpy (&md5->buffer[index], input, part_len);
		__transform (md5->state, md5->buffer);

		for (i = part_len; i + 63 < len; i += 64) 
			__transform (md5->state, &input[i]);
		index = 0;	
	}
	else i = 0;

	/* buffer remaining input */
	xp_memcpy (&md5->buffer[index], &input[i], len - i);
}

xp_size_t xp_md5_digest (xp_md5_t* md5, xp_byte_t* digest, xp_size_t size)
{
	xp_byte_t bits[8];
	xp_uint32_t index, pad_len;

	if (size < 16) return 0;

	/* save number of bits */
	__encode (bits, md5->count, 8);

	/* pad out to 56 mod 64 */
	index = (xp_uint32_t)((md5->count[0] >> 3) & 0x3F);
	pad_len = (index < 56)? (56 - index): (120 - index);
	xp_md5_update (md5, padding, pad_len);

	/* append length (before padding) */
	xp_md5_update (md5, bits, 8);

	/* store state in digest */
	__encode (digest, md5->state, 16);
	__init (md5);

	return 16;
}

static void __init (xp_md5_t* md5)
{
	md5->count[0] = 0;
	md5->count[1] = 0;

	md5->state[0] = 0x67452301;
	md5->state[1] = 0xEFCDAB89;
	md5->state[2] = 0x98BADCFE;
	md5->state[3] = 0x10325476;
}

static void __transform (xp_uint32_t state[4], xp_byte_t block[64])
{
	xp_uint32_t a, b, c, d, x[16];

	a = state[0];
	b = state[1];
	c = state[2];
	d = state[3];

	__decode (x, block, 64);

	/* Round 1 */
	FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
	FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
	FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
	FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
	FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
	FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
	FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
	FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
	FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
	FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
	FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
	FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
	FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
	FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
	FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
	FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

	/* Round 2 */
	GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
	GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
	GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
	GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
	GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
	GG (d, a, b, c, x[10], S22,  0x2441453); /* 22 */
	GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
	GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
	GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
	GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
	GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */

	GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
	GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
	GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
	GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
	GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

	/* Round 3 */
	HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
	HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
	HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
	HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
	HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
	HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
	HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
	HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
	HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
	HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
	HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
	HH (b, c, d, a, x[ 6], S34,  0x4881d05); /* 44 */
	HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
	HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
	HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
	HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */

	/* Round 4 */
	II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
	II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
	II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
	II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
	II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
	II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
	II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
	II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
	II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
	II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
	II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
	II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
	II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
	II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
	II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
	II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */

	state[0] += a;
	state[1] += b;
	state[2] += c;
	state[3] += d;
}

static void __encode (xp_byte_t* output, xp_uint32_t* input, xp_size_t len)
{
	xp_size_t i, j;
	
	for (i = 0, j = 0; j < len; i++, j+=4) {
		output[j + 0] = (xp_byte_t)((input[i] >>  0) & 0xFF);
		output[j + 1] = (xp_byte_t)((input[i] >>  8) & 0xFF);
		output[j + 2] = (xp_byte_t)((input[i] >> 16) & 0xFF);
		output[j + 3] = (xp_byte_t)((input[i] >> 24) & 0xFF);
	}
}

static void __decode (xp_uint32_t* output, xp_byte_t* input, xp_size_t len)
{
	xp_size_t i, j;

	for (i = 0, j = 0; j < len; i++, j+=4) {
		output[i] = input[j] | (input[j + 1] << 8) | 
			(input[j + 2] << 16) | (input[j + 3] << 24);
	}
}
